Motor driven step opening gas supply unit



Dec. 14, 1965 T. E. NOAKES ETAL 3,223,143

MOTOR DRIVEN STEP OPENING GAS SUPPLY UNIT Filed June 14, 1962 LLECTE. lC MOTOR 86 sPRmq MOTOR FILL].

amino: 57 mNl'ron Z7 29 j? F 15.6 Z5 Z5 52% INVENTORS United States Patent 3,223,143 MOTOR DRIVENSTEP OPENING GAS SUPPLY UNIT Thomas E. Noalrcs, Detroit, Maynard E. Anderson, Birmingham, and Melvin W. Poliringhorn, Livonia, Mich, assignors to American Radiator & Standard Sanitary Corporation, New York, N.Y., a corporation of Delaware Filed June 14, 1962, Ser. No. 202,464 13 Claims. (Cl. 153 -125) This invention relates to an electrically controlled fuel supply unit for gas burners such as are used for example in domestic space heaters and clothes dryers.

One object of the invention is to provide a step-opening fuel supply unit which initially supplies a small flow of gas to the burner for a predetermined short time period, which thereafter supplies the burner with a large fiow of gas if the burner has been able to ignite the small flow, or discontinues all gas flow to the burner if it has been unable to ignite the small flow.

As related to the above, it is a principal object to provide a step-opening gas valve which eliminates the combustion puif which sometimes occurs when conventional gas valves are abruptly turned from full off to full on.

Another object of the invention is to provide a stepopening fuel supply unit wherein the duration of the small flow period is precisely controlled by a mechanical connection between the electrical section and the valve section.

A further object of the invention is to provide a stepopening fuel supply unit which incorporates a pressure regulator for delivering the gas flow at a substantially constant pressure.

An additional object is to provide an electrically-controlled step-opening fuel supply unit which is powered solely by a single rotary electric motor.

A still further object of the invention is to provide an electrically controlled step-opening fuel supply unit which incorporates a simply wired power circuit.

Another object is to provide a step-opening fuel valve which has fail-safe operation, and which during startup is incapable of recycling in the event of no flame.

A further object is to provide a gas supply unit which acts as a high fire control, a low fire control and a pressure regulator, these three functions being performed by only two throttling ports so that the usual low pressure source gases can be handled without excessive pressure drop in the unit.

Other objects of this invention will appear from the following description and appended claims, reference being had to the accompanying drawings forming a part of this specification wherein like reference characters designate corresponding parts in the several views.

In the drawings:

FIGURE 1 is a sectional view of a gas supply unit incorporating features of the invention;

FIG. 2 is a fragmentary view taken on a reduced scale along line 22 in FIG. 1;

FIG. 3 is a fragmentary view taken on a reduced scale along line 33 in FIG. 1;

FIG. 4 is a fragmentary view taken in the FIG. 2 direction but showing the illustrated components in the position occupied during start-up operations;

FIG. 5 is a fragmentary view taken in the FIG. 3 direction but showing the illustrated components in the start-up positions of FIG. 4;

FIG. 6 is a fragmentary view taken in the FIG. 2 direction but showing the illustrated components in the position occupied during normal run operations;

FIG. 7 is a fragmentary view taken in the FIG. 3 direction but showing the illustrated components in the normal run position of FIG. 6;

FIG. 8 is a diagram of a control wiring arrangement which can be used for the FIG. 1 unit; and

FIG. 9 is a diagram of a second control wiring arrangement which can be used for the FIG. 1 unit.

Before explaining the present invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and arrangement of parts illustrated in the accompanying drawings, since the invention is capable of other embodiments and of being practiced or carried out in various ways. Also, it is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation.

Referring to FIG. 8 of the drawings, there is schematically shown a gas supply valve section 10, and an electrical control section 12 including an electric motor 48. Valve section It) is arranged in a fuel gas supply line and is mechanically connected with motor 48 so that it either completely interrupts gas flow, or supplies burner 11 with a small start-up flow of gas through line 15, or supplies burner 11 with a larger normal-run flow of gas through line 17.

Motor 48 is controlled by a motor-driven control switch 19 which is operable between its illustrated start-up position and a normal run position in which it feeds line 21 with current. Switch 19 is arranged so that during the start-up period it by itself sustains valve-opening movement of motor 48, but during normal running operations it depends on the presence of a burner flame to keep the motor energized. To this end, line 21 from switch 19 terminates in a hot contact 23 for conventional flame detector switch 25. The cold detector contact 27 connects with a suitable electric igniter 28 such as a glow coil. The common terminal 29 of detector switch 25 connects with the motor-energizer line 31a via a connector line 33.

In operation, the components assume their FIG. 8 positions prior to normal start-up. When thermostatic or manual switch 35 calls for heat motor 48 isenergize'd via switch 19; simultaneously ignitor 28 is energized via switch 19, line 31, line 33, switch 25, cold contact 27 and line 37. After a predetermined time, as for example three seconds, motor 48 will have moved sufiiciently to have provided an ignitable supply of gas at the small burner element 41. Assuming ignitor 28 is able to ignite this gas, detector 25 will within the next few seconds have shifted to hot contact 23 to de-energize the ignitor. Motor 48 will continue to run and at some point will operate switch 19 to its running position connecting with line 21. At this point motor energization will be through line 21, detector 25, line 33, line 31a, the motor, and line 31b. Continued motor energization operates valve section 10 to a condition wherein a large flow of gas is supplied to burner unit 11 via line 17. Thereafter motor 48 will hold in a'st'alled normal running condition against the force of a valve return spring (not shown in FIG. 8) until switch 35 is opened, whereupon the motor and valve section will be returned to their start or off positions.

If ignitor 28 had not been able to ignite the small flow of gas from line 15 detector 25 would remain in its cold position so that when control switch 19 was moved by motor 48 up to its run position the motor would deenergize before continuing to the position for opening gas line 17. This action prevents the discharge of large gas flows to the burner when there is no previous ignition of the small gas flow.

Referring now in greater detail to the drawings, FIG. 1 shows a fuel supply unit for a gas burner comprising a lower gas supply valve section and an upper electrical control section 12. The valve section comprises a valve housing 13 having a gas inlet chamber 14, a first valveseat 16, a first upwardly opening cavity 18, a second upwardly opening cavity 20, a cavity-communication opening 22, a second valve seat 24, and an outlet chamber 26. Overlying each cavity is a rubber diaphragm or 32 having slack (not shown) therein for enabling it to move vertically with the connected valve stem 34 or 36 and valve element 38 or 40. A relatively small opening 42 is provided in housing 13 to feed burner element 41 with a small flow of gas during burner start-up operations. The larger normalrun gas flow for the main burner takes place through valve seat 24.

The aforementioned electrical control section 12 comprises a cover 44 suitably bolted to housing 13 and having a bracket-like platform member 46 for supporting an electric motor-speed reduction unit generally designated by numeral 48. Preferably unit 48 is constructed as shown in US. Patents 2,334,040 and 2,353,305. The drive shaft 49 from unit 48 is constructed with a threaded area 50 which cooperates with a tongue 53 in lever 52 so that counterclockwise movement of shaft 49 (looking downward) causes a pivotal lowering movement of the lever from its illustrated position.

The right end portion 55 of lever 52 is bifurcated such that it clears stem 34 and is capable of movement between spring retainer 54 and fixed stop 56. Retainer 54 engages spring 58 so that the spring force is transmitted to lever 52 for the initial part of its downward movement. During this initial part of the movement the extreme left tip area of lever 52 abuts on the underface of cover 44 and acts as a fulcrum for the lever. After lever end portion 55 engages stop 56 it acts as a fulcrum to permit the left end portion of the lever to move downwardly for opening valve element 40.

While lever end portion 55 is engaged with stop 56 spring 58 acts on diaphragm 30 so that cooperating valve element 38 performs a pressure regulating function. Thus, element 38 constitutes'a main shut-off and a pressure regulator for maintaining constant pressure in chamber 18 irrespective of substantial variations in supply pressure. The general opening sequence involves opening of valve element 38 to provide the small flow of gas through port 42, and then an opening of valve element to provide the large flow of gas through chamber 26. While element 38 is open it acts as a pressure regulator. Screw 60 can be adjusted to provide the desired pressure setting.

Referring now to control switch 19, said switch is of the snap-action type and is provided with an operating pin 62 and spring-arm actuator 64, the roller 66 of which rides on the peripheral edge of a rotary cam disc 68. The edge area between disc edge points 69 and 71 defines a circumferential cam surface, while the remainder of the disc periphery is concentric with the axis of shaft 49. Therefore arm 64 moves only when roller 66 engages the disc areas between points 69 and 71.

As seen in FIG. 2, disc 68 is provided with a radially enlarged sector opening 70 and a narrow slot-like track 72. Overlying disc 68 is a plate 74 having a rectangular opening therein for keying itself on the non-circular portion of shaft 49. As best seen in FIG. 1, plate 74 is provided with a vertical drive pin or power member 76 which extends from both faces of the plate so that its lower portion is located in the opening 70, 72 in disc 68 and its upper portion is located in horizontal alignment with cam-forming projections 80, 82 and 84 depending from a plate 85 which is fixedly carried on platform 46. This platform defines a well for receiving a clock-type spring motor 86, the ends of which connect with members 46 and 49, respectively.

FIGS. 2 and 3 show the components in the start-up position of FIG. 8. As motor 48 is energized pin 76 moves 38 begins to open. Pin 76 at this time strikes disc surface 88 and thus begins to rotate disc 68 counterclockwise. Continued movement brings pin 76 into engagement with fixed cam 82 so that the pin is shifted radially inwardly into circumferential registry with track 72; during this movement point 69 on cam 68 passes roller 66 so that spring arm 64 begins to move away from switch 19 toward its FIG. 4 position. Before the FIG. 4 position is reached ignitor 28 should have ignited the small flow of gas coming from opening 42 (FIG. 1).

When pin '76 reaches the FIG. 4 position switch 19 has undergone snap action to the run position. If ignitor 28 has been able to ignite the small flow of gas, detector 25 will be in its hot position engaged with contact 23, and motor 48 will continue the motion of pin 76 to its FIG. 6 position. Valve element 40 starts to open about halfway between the FIG. 4 and FIG. 6 positions, and is fully open when the FIG. 6 position is reached. At the FIG. 6 position motor 48 stalls, and spring motor 86 is loaded for later returning the components to the FIG. 2 position.

During the FIG. 4 to FIG. 6 movement pin 76 rides on the outer face of cam 84 so that in the FIG. 6 position it is located radially outwardly in opening 70. Therefore when switch 35 (FIG. 8) is opened motor 86 acts on pin 76 to move it against disc surface 90 (FIG. 6) for thereby returning the components to the FIG. 2, 3 position. The start-up time required to go from the FIG. 2 position to the FIG. 6 position is definite but preferably quite short, as for example ten seconds. The shutdown time to return from the FIG. 6 position to the FIG. 2 position is preferably in the range of three seconds.

Assuming that during the start-up operation ignitor 28 had failed to ignite the small flow from opening 42; when the FIG. 4 position was reached switch 19 would be actuated to connect with line 21 whereas detector switch 25 would be engaged with cold contact 27. Under these circumstances motor 48 would be de-energized and pin 76 would thereupon return in track 72 without moving disc 68. The electrical control is thereby locked out from a further attempt at ignition.

To provide for manual reset there may be provided a lever 94 having a manual push button portion 96 arranged so that manual operation thereof moves spring arm 64 to the FIG. 2 start-up position. In this position motor 48 is energized to move pin 76 counterclockwise along track 72 and to also introduce a small flow of gas to the burner via opening 42.

As previously noted, the FIG. 1 gas supply unit may be controlled electrically by the FIG. 8 circuit. If desired the control circuit could take other forms, as for example that shown in FIG. 9. In the FIG. 9 arrangement the flame detector comprises a flame-responsive electric valve in the form of a photoconductive cell 25a; control switch 19 is provided as a single pole switch. The photoconductive cell may be of conventional construction, as for example a cadmium sulfide cell which in the presence of flame has a low electrical impedance and which in the absence of flame has a high electrical impedance.

In operation, at start-up the closing of thermostat 35 causes start-up current to feed to motor 48 through switch 19. When switch 19 is opened by motor action (as in the FIG. 4 position) the motor current will have been supplied through cell 25a if flame has been established by the igniting means (not pictured in FIG. 9). If no flame has been established the dark cell will not pass current to the motor. The general sequence of operations is the same as in the case when the FIG. 8 control circuit is utilized.

It is believed that with the above discussion the general features of the invention will be understood. In practicing the invention some structural variations in form can be utilized. For example, opening 42 (FIG. 1) could discharge into chamber 26, in which case both the small gas flow and the large gas flow would take place through line 17; small burner 41 would then be omitted. The screw-type connection between shaft 49 and lever 52 could be replaced by another type connection, as for example a cam type connection. The use of a clock type spring 86 is convenient, although other types of springs could be employed. Other variations are possible. The scope of the invention is set forth in the appended claims.

We claim:

1. In a fuel supply unit for a gas burner: a fluid valve section means and an electrical control section means comprising an electric motor mechanically interconnected with the valve section means to provide a cycle wherein initial energization of the electrical section means is effective (1) to cause the valve section means to introduce a small flow of gas to a burner for a predetermined time period, (2) to thereafter introduce a large flow of gas to a burner upon ignition of the small flow, and (3) to discontinue the gas flow if the burner has been unable to ignite the small flow; said electrical section means including further means responsive to the absence of burner flame to completely de-energize the electrical section means so that it cannot automatically cause the fluid valve section means to thereafter feed gas to the burner; said responsive means comprising an electrical switch automatically operable by motor movement from a first starting condition wherein it by itself sustains valve-opening movement of the electrical section to a second running condition wherein it depends on the presence of burner flame to sustain valve-opening movement of the electrical section means.

2. In a fuel supply unit for a gas burner: a fluid valve section means and an electrical control section means interconnected so that initial energization of the electrical section means is effective to cause the valve section means to introduce a small flow of gas to a burner for a predetermined time period, to thereafter introduce a large flow of gas to a burner if it has been able to ignite tne small flow, or to discontinue the gas flow if the burner has been unable to ignite the small flow; said fluid valve section means comprising two separate valve elements arranged in series flow relationship so that the downstream valve element interrupts the large flow of gas to a burner and the upstream valve element controls both the aforementioned small gas flow and the gas supply for the downstream element; said electrical control section means comprising a single rotary electric motor and a mechanical connection means between the motor and both valve elements for initially opening the upstream valve element, then disengaging the upstream valve element, and then opening the downstream valve element; said mechanical connection means comprising a lever having a central portion connected with the motor, and end portions connected with the respective valve elements.

3. The combination of claim 2 wherein the mechanical connection means further comprises a motor drive shaft having a threaded area and a cooperating area on the lever so that motor rotation effects movement of the lever.

4. In a fuel supply unit for a gas burner: a valve housing having two communicating cavities in its upper face, and valve seat means in the cavity bottom walls arranged so that gas can flow through one seat into the two cavtiies and out the other valve seat; a diaphragm extending across the mouth of each cavity to constitute a seal; one of said cavities having a continuously open connection with a burner for supplying same with a small flow of gas; a stem-valve element means carried by the diaphragm for controlling gas flow through the respective seats; an electrical control means including an electric motor mechanically connected with the valve element stems so that 1) initially the upstream valve element opens for supplying a small flow of gas to a burner via the aforementioned connection, and (2) thereafter the downstream valve element opens for supplying a large flow of gas to a burner if it has been able to ignite the small 6 flow, or the upstream valve element closes if the burner has been unable to ignite the small flow.

5. In a fuel supply unit for a gas burner: a valve housing having two communicating cavities in its upper face, and valve seat means in the cavity bottom walls arranged so that gas can flow through one seat into the two cavities and out the other valve seat; a diaphragm extending across the mouth of each cavity to constitute a seal; one of said cavities having a continuously open connection with a burner for supplying same with a small flow of gas; a stem-valve element means carried by the diaphragm for controlling gas flow through the respective seats; an electrical control means including an electric motor mechanically connected with the valve element stems so that (I) initially the upstream valve element opens for supplying a small flow of gas to a burner via the aforementioned connection, and (2) thereafter the downstream valve element opens for supplying a large flow of gas to the burner if it has been able to ignite the small flow, or the upstream valve element closes if the burner has been unable to ignite the small flow; said upstream valve element and the diaphragm operating as a pressure regulator for maintaining the pressure of the gas flow substantially constant irrespective of substantial variation in the gas supply pressure.

6. In a fuel supply unit for a gas burner: a valve housing having two communicating cavities in its upper face, and valve seat means in the cavity bottom walls arranged so that gas can flow through one seat into the two cavities and out the other valve seat; a diaphragm extending across the mouth of each cavity to constitute a seal; one of said cavities having a continuously open connection with a burner for supplying same with a small flow of gas; a stem-valve element means carried by the diaphragm for controlling gas flow through the respective seats; an electrical control means including an electric motor mechanically connected with the valve element stems so that (1) initially the upstream valve element opens for supplying a small flow of gas to a burner via the aforementioned connection, and (2) thereafter the downstream valve element opens for supplying a large flow of gas to a burner if it has been able to ignite the small flow, or the upstream Valve element closes if the burner has been unable to ignite the small flow; the upstream portion of the diaphragm having a calibrated compression spring acting downwardly thereon to exert a regulated force opposing closing movement of the upstream valve element, whereby the upstream valve element and diaphragm constitute a pressure regulator for maintaining the pressure of gas flowing through the downstream seat substantially constant irrespective of substantial variations in the gas supply pressure.

7. In a fuel supply unit for a gas burner: a valve housing having two communicating cavities in its upper face, and valve seat means in the cavity bottom Walls arranged so that gas can flow through one seat into the two cavities and out the other valve seat; a diaphragm extending across the mouth of each cavity to constitute a seal; one of said cavities having a continuously open connection with a burner for supplying same with a small flow of gas; a stem-valve element means carried by the diaphragm for controlling gas flow through the respective seats; an electrical control means including an electric motor mechanically connected with the valve element stems so that (1) initially the upstream valve element opens for supplying a small flow of gas to a burner via the aforementioned connection, and (2) thereafter the downstream valve element opens for supplying a large flow of gas to a burner if it has been able to ignite the small flow, or the upstream valve element closes if the burner has been unable to ignite the small flow; the upstream portion of the diaphragm having a calibrated compression spring acting downwardly thereon to exert a regulated force opposing closing movement of the upstream valve element, whereby the upstream valve element and diaphragm constitute a pressure regulator for maintaining the pressure of gas flowing through the downstream seat substantially constant irrespective of substantial variations in the gas supply pressure; and disengageable connection means between the stem and electric motor so that the upstream portion of the diaphragm can freely reciprocate when acting as a pressure regulator.

8. In a fuel supply unit for a gas burner: a valve housing having a first valve means operable to admit gas to a burner, and pressure regulator means including a second valve means movable back-and-forth for regulating the pressure of the gas flowing through the first valve means; an electrical control means carried on the valve housing, including a single rotary electrical motor having a disengageable connection with the pressure regulator valve means whereby energization of the motor is eflective to permit the regulator element to assume its regulating range of movement, and de-energization of the motor is effective to close the pressure regulator means to gas flow therethrough.

9. In a fuel supply unit for a gas burner: a flame detector comprising a switch having a cold contact and a hot contact; an electric flame ignitor connected with the flame detector cold contact; a valve section means operable between a first position in which it interrupts gas flow to a burner, to a second position in which it introduces a small flow of gas to a burner, and a third position in which it introduces a large flow of gas to a burner; an electric motor means mechanically connected with the valve section means for moving same between its three positions; an electrical control switch having a starting contact connected with the motor means and a running contact connected with the flame detector hot contact; electrical connections between the control switch starting contact, the flame detector switch, and the electric motor means; and means driven from the motor means for operating the control switch so that initial energization of the motor means via the starting contact causes the valve section means to introduce a small flow of gas to a burner, after which the control switch is operated to connect with its running contact, whereupon (1) if the detector switch is connected with its hot contact current will be supplied to the motor means for operating the valve section means to a position in which it introduces a large flow of gas to a burner, or (2) if the detector switch is connected with its cold contact the motor means will be de-energized for causing the valve section means to move to a position interrupting gas flow to the burner.

10. In a fuel supply unit for a gas burner: an electric flame detector; an electric flame ignitor means receiving current via the detector in the absence of flame; a valve section means operable between a first position in which it interrupts gas flow to a burner, a second position in which it introduces a small flow of gas to a burner, and a third position in which it introduces a large flow of gas to a burner; an electric motor means mechanically connected with the valve section means for moving same between its three positions; and a control switch means driven by the motor means and electrically connected with the detector and motor means so that in one position it by itself supplies motor means current and in another position it depends on a flame ignition sensed by the detector for supplying motor means current; said motor means and ignitor means being initially energized via the control switch means and detector to provide a small flow of ignitable gas at the burner, after which the control switch means is automatically operated by the motor means to disconnect the ignitor means and (1) if the detector senses flame to continue to deliver motor means current for causing a large flow of gas to a burner, or (2) if the detector senses flame failure to interrupt motor current and thereby interrupt gas flow to a burner.

11. In a fuel supply unit for a gas burner: a fluid valve section means and an electrical control section means interconnected so that initial energization of the electrical section means is effective to cause the valve section means to introduce a small flow of gas to a burner for a predetermined time period, to thereafter introduce a large flow of gas to a burner upon ignition, and to discontinue the gas flow upon the burner being extinguished; said electrical control section means comprising a rotary electric motor energizable to power the valve section means in the flow-increasing direction, a spring motor means operable to power the valve section means in the flow de- I creasing direction, an electric motor control switch means operable by motor movement from a starting condition wherein it by itself sustains motor energization to a running condition wherein said control switch means depends on the presence of burner flame to sustain motor energization; and a lost motion mechanical connection means between the control switch means and motor whereby the motor drives the switch means from its starting condition to its running condition after admission of a small flow of gas to the burner, whereupon the absence of burner flame de-energizes the electric motor and allows the spring motor means to return the valve section means to an off condition without returning the control switch means to its starting condition.

12. The combination of claim 11 wherein the lost motion mechanical connection means comprises a switchoperating cam means and a motor-driven power member operably engaged with said cam means having a first tracking path in which it operates the cam during motor energized movement and a second tracking path in which it returns to a starting position without operating the cam.

13. In a fuel supply unit for a gas burner, a valve section means operable between a first position in which it interrupts gas flow to a burner, to a second position in which it introduces a small flow of gas to a burner, 21 third position in which it introduces a large flow of gas to a burner; an electric motor mechanically connected with the valve section means for moving same between its three positions; an electrical control circuit means for the motor comprising a control switch means and flame detector, said control switch means being mechanically operated by the motor so that in one position it alone supplies motor current for causing the motor to move to a position in which a small flow of ignitable gas is supplied to a burner, after which the motor operates the control switch means to a second position in which it and the flame detector cooperatively supply motor current for moving the valve section means to a position in which a large flow of gas is supplied to the burner.

References Cited by the Examiner UNITED STATES PATENTS 1,796,544 3/1931 Shivers 236--92 2,138,796 11/1938 Sparrow 158-28 2,709,486 5/1955 Kik 158--131 X 2,743,870 5/1956 Drow 236--1 2,850,031 9/1958 Meusy 158-431 X 2,851,095 9/1958 Aubert 158123 X 2,958,377 11/1960 Laing l58l31 X 3,045,690 7/1962 Nickells 158130 X 3,060,997 10/1962 Maney I5828 FREDERICK L. MATTESON, IR., Primary Examiner.

PERCY L. PATRICK, JAMES W. WESTHAVER,

Examiners. 

8. IN A FUEL SUPPLY UNIT FOR A GAS BURNER: A VALVE HOUSING HAVING A FIRST VALVE MEANS OPERABLE TO ADMIT GAS TO A BURNER, AND PRESSURE REGULATOR MEANS INCLUDING A SECOND VALVE MEANS MOVABLE BACK-AND-FORTH FOR REGULATING THE PRESSURE OF THE GAS FLOW THROUGH THE FIRST VALVE MEANS; AN ELECTRICAL CONTROL MEANS CARRIED ON THE VALVE HOUSING, INCLUDING A SINGLE ROTARY ELECTRICAL MOTOR HAVING A DISENGAGEABLE CONNECTION WITH THE PRESSURE REGULATOR VALVE MEANS WHEREBY ENERGIZATION OF THE MOTOR IS EFFECTIVE TO PERMIT THE REGULATOR ELEMENT TO ASSUME ITS REGULATING RANGE OF MOVEMENT, AND DE-ENERGIZATION OF THE MOTOR IS EFFECTIVE TO CLOSE THE PRESSURE REGULATOR MEANS TO GAS FLOW THERETHROUGH. 